Design patterns are widely-used software engineering abstractions which define guidelines for modeling common application scenarios. Ontology design patterns are the extension of software patterns for knowledge acquisition in the Semantic Web. In this work we present a design pattern for representing relevance depending on context in OWL ontologies, i.e. to assert which knowledge from the domain ought to be considered in a given scenario. Besides the formal semantics and the features of the pattern, we describe a reasoning procedure to extract relevant knowledge in the resulting ontology and a plug-in for Prot´eg´e which assists pattern use.